How to sharpen drills for metal correctly

How to sharpen drills for metal correctly? — Metals, equipment, instructions

When drilling metal, the cutting tool loses its initial sharpness of the working edge. Don't throw it away to buy a new one.

Even the strongest grade of steel, subject to heat treatment, cannot ensure drilling operations without restoring the cutting part. Sharpening a drill for metal will help restore its previous performance properties.

It is easy to make a device with your own hands at home without the use of special equipment. Let's look at how to return a tool to its original cutting properties.

How does the sharpening angle of a metal drill affect drilling efficiency?

At home, work is often done to make holes of the required size in metal. When drilling, it is not always possible to quickly replace a worn-out tool with a new one of the required size. Home craftsmen try to select the required diameter, but if the sharpening angles of the drills are not maintained, then it is problematic to quickly and efficiently complete the task.

The discrepancy between the sharpness of the cutting edge and geometric parameters can be determined by a number of signs:

increased noise level emitted by an unsharpened shank;
intensive increase in the temperature of the workpiece during machining;
sudden heating of the working part and the body fixed in the cartridge;
unsatisfactory quality of formed holes;
an increase in the axial force applied to the electric drill;
the quality of the chips, which crumble and do not have a spiral shape.

Drills intended for metal work have to be sharpened much more often than those used for wood processing.

In addition, the load on the electric motor increases significantly when trying to apply a force in the axial direction sufficient to immerse the cutting edge into the metal. The dullness of the chamfer is a source of additional resistance between the cutting part and the processing surface. Knowing how to properly sharpen a drill for metal, if any of these signs are detected, you must immediately stop drilling and begin restoration.

A worn working part not only reduces machining efficiency, but also affects safety. At high temperatures and elevated temperatures, performing machining at significant speeds, breakdown is possible. Metal fragments can fly in all directions and cause serious injury.

Sharpening drills - preparatory activities

Home craftsmen are often upset by the impossibility of further implementation of plans due to the fact that the drill has become dull. How to sharpen it yourself? Indeed, in the conditions of manufacturing enterprises, special equipment is used to solve such a problem.

It allows for increased accuracy, securely fixes the cutting shank and restores the condition of the cutting edge in a limited time. When thinking about how to sharpen a metal drill at home, check what household power tools are available.

The following equipment will be suitable:

Sander;
grinder;
electric drill.

You should carefully consider what you will need to complete the work and what you will need to add to the power tool.

Sharpening a drill for metal using a special device greatly simplifies the task

Do-it-yourself drill sharpening should be done using additional accessories:

grinding wheels of varying hardness. The grain size of the wheel is selected depending on the hardness of the material being processed;
container intended for coolant. In terms of cooling efficiency, machine oil will provide a greater effect than ordinary water;
a fixing device to ensure the required sharpening angle. It is important to ensure reliable fixation when processing the cutting part.

To ensure immobility, a complex adjustable angle jig or a simple drill bit sharpener can be used on a drill.

Source: https://spb-metalloobrabotka.com/kak-pravilno-tochit-sverla-po-metallu/

How to sharpen a drill for metal and what sharpening angles are there?

Twist drills are used to create holes in metals. No matter how durable the tip material is, sooner or later the tool will lose the sharpness of the cutting edge. Signs of dullness:

when rubbing against a workpiece, a sharp creak is heard;
the chips come out in small crumbs, not in a spiral;
During drilling, intense heat occurs.

If any of these signs are present, you will need to sharpen your drill bit. Moreover, there is no need to wait for the sharp edges to be completely ground down. When working with a blunt tip, it becomes so hot that the hardened metal “relaxes” and rapidly degrades.

It would be better for you to reduce the length of the tool by 0.5-1 mm with each sharpening, but the device will always be sharp and will last longer.

The next extreme is to throw away the blunt instrument and buy a new one. You don't throw away dull knives or an ax, do you? So the drills need to be sharpened. Unlike cutting tools, this process is regulated by certain standards.

How to sharpen a drill correctly, what sharpening angles exist

The main angle at the tip, which determines the ability to process different metals, is the development of the tip edges.

Its value varies for different materials.

Hard steel – 140°;
Stainless steel – 135°-140°;
Deep drilling – 130°;
Cast iron - double angle. Main – 118°, auxiliary – 90°;
Aluminium, brass, bronze – 118°;
Copper and alloys based on it – 100°.

To understand how to properly sharpen different angles, you need to understand how many of them the drill has and where they are located. For example, consider the components of the working part and the tip angles for processing stainless steel:

As you can see, the tool consists of a large number of components, each of which does its own job. However, not all edges will have to be sharpened by hand. Yes, and you can control the process using a universal template.

Metal drills look the same, with the exception of special models that are not used in everyday life.

The shank and neck require no maintenance. Of the working part, only the cutting part is sharpened. The ribbon, intended for the formation and removal of chips, is manufactured at the factory. It is almost impossible to process it at home or even in an industrial environment.

The cutting edge consists of a back and front surface that meet at an acute angle. It is this edge that scrapes chips from the workpiece, going deeper into the surface and forming a hole.

If the edge is not sharp, has dents and irregularities, drilling becomes very difficult, and banal idle friction of metal on metal occurs.

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Unlike a knife or an axe, a simple whetstone is not enough. For sharpening, you will need an abrasive wheel rotating at speeds of up to 1500 rpm. The most convenient device is a sharpening machine.

The disc must be fine-grained. The size of the fraction according to the standard marking is 8H-16H. The material of the emery wheel is silicon carbide. Such abrasives have a characteristic greenish tint. Material marking – 64C.

Experienced craftsmen sharpen by hand, using only a tool. The correctness of the angles is checked with a template. However, there are a number of devices to facilitate work and increase processing accuracy.

The choice is quite wide, you can choose a machine to suit every taste and budget. Many “Kulibins” make their own devices.

You just need to set the required angle according to the table, secure the drill in the rack - and control the heating.

Therefore, you need to feed the tool with short movements, 2-3 seconds each. If necessary, after each approach the tip can be cooled with water and dissolved soda.

If you work with drills on an industrial scale, it makes sense to buy a semi-automatic sharpening machine. This can be a separate specialized machine

so is the attachment for a power tool.

In both cases, your participation in the work is minimal. The quality of processing in such devices is ideal, but the cost is quite high.

Don't despair, the wise Chinese have figured out how to sharpen drills inexpensively and efficiently. The attachment on a regular screwdriver does the job slowly, but efficiently. And the price tag is more than humane.

And yet let's return to the traditional manual method.

This is exactly how almost all home mechanics sharpen metal drills.

Before starting work, you need to decide what type of sharpening you need to process the working part of the drill. Cutting edges are sharpened in the following ways:

single-plane;
two-plane;
conical;
cylindrical;
screw.

First, the back surface of the edge is sharpened. The thickness of the removed material should be such that not a single defect remains on the edge. If there are dents of 1-2 mm on the drill, you will have to shorten the nozzle to this length.

During the process, we periodically inspect the working edge. The edges must be symmetrical, the jumper must be smooth, and be located exactly in the middle between the working edges.

Drills with a diameter of up to 3 mm are sharpened using a single-plane method. After giving the correct shape to the back surface, the drill using a tool rest or other device is pressed against the sandpaper at an angle of 25°-30°.

During the sharpening process, the drill should not be rotated or changed angle. This is necessary to give the edge a perfectly flat shape. In addition, when turning, part of the metal of the working edge may crumble.

A tool of such a small diameter can be sharpened in one go, so there is no need to worry about overheating.
You can cool the drill in a soda solution when changing the sharpening plane. We inspect the working tip - the edges should be identical and have an equal angle of inclination.

We check the correct angle using the template. If it doesn’t work out the first time, you can’t rework the edge. It needs to be sharpened again.

Tools with a diameter of more than 4 mm are sharpened using a conical method. The technique requires certain skills, so before processing valuable drills you should practice on those that you don’t mind ruining.

ADVICE! Try not to throw away broken drill bits. Firstly, you can practice sharpening skills on them, and secondly, the shank of a broken tool can be used as a drift or cotter pin.

The conical method is fundamentally different from the single-plane method. The drill is held with two hands (the size of large specimens allows this). After the cutting edge touches the abrasive, the drill is rotated along the back side to give it a conical shape.

After each approach, the working part is checked against the templates in all three corners.

You can sharpen large drills using a planar method. However, with this method, the drill will have difficulty removing chips from the hole and will overheat greatly.

How to store new and sharpened drill bits

When storing and carrying, drills should not rub against each other. When you take the tool out of the common box, the sharp working edges become dull against their neighbors. The best option is individual holes or sleeves for vertical storage. And if you sign the dimensions, searching for a drill of the required diameter will not take much time.

Of course, indoor humidity should not lead to corrosion.
For a detailed description of how to properly sharpen a drill, watch this video.

Source: https://obinstrumente.ru/ruchnoj-instrument/kak-zatochit-sverlo-po-metallu.html

1 How to sharpen a drill for metal and what sharpening angles are there?
2 Sharpening a drill for metal: parameters, tools for work, useful sharpening tips at home
3 How to sharpen a metal drill yourself
4 How to properly sharpen a drill for metal + video
5 Sharpening a drill for metal
6 How to sharpen a metal drill correctly?
7 How to sharpen a drill for metal and concrete with your own hands
8 How to sharpen a metal drill using different tools
9 How to properly sharpen a metal drill with your own hands
10 How to properly sharpen a drill for metal
11 Sharpening a metal drill with your own hands
12 How to properly sharpen a metal drill with your own hands - detailed instructions
13 How to sharpen a metal drill with your own hands +

Twist drills are used to create holes in metals. No matter how durable the tip material is, sooner or later the tool will lose the sharpness of the cutting edge. Signs of dullness:

when rubbing against a workpiece, a sharp creak is heard;
the chips come out in small crumbs, not in a spiral;
During drilling, intense heat occurs.

It would be better for you to reduce the length of the tool by 0.5-1 mm with each sharpening, but the device will always be sharp and will last longer.

How to sharpen a drill for metal

Unlike a knife or an axe, a simple whetstone is not enough. For sharpening, you will need an abrasive wheel rotating at speeds of up to 1500 rpm. The most convenient device is a sharpening machine.

The disc must be fine-grained. The size of the fraction according to the standard marking is 8H-16H. The material of the emery wheel is silicon carbide. Such abrasives have a characteristic greenish tint. Material marking – 64C.

The choice is quite wide, you can choose a machine to suit every taste and budget. Many “Kulibins” make their own devices.

You just need to set the required angle according to the table, secure the drill in the rack - and control the heating.

Therefore, you need to feed the tool with short movements, 2-3 seconds each. If necessary, after each approach the tip can be cooled with water and dissolved soda.

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https://www.youtube.com/watch?v=wY2X2IkNmf8

If you work with drills on an industrial scale, it makes sense to buy a semi-automatic sharpening machine. This can be a separate specialized machine

Source: https://steelfactoryrus.com/kak-pravilno-tochit-sverla-po-metallu/

Methods of drilling metal: drills and fixtures

We will learn all the intricacies and methods of drilling metal - choosing a tool, sharpening and cutting modes.

Drilling a hole in metal - what could be easier? There are, however, quite a few subtleties in this metalworking operation regarding the correct choice of tool, sharpening and cutting modes.

How to drill a hole in metal

Types of metal drills and sharpening techniques
How to drill metal correctly

To make holes in metal, drills are used - mechanical rods made of an alloy that is harder than the workpiece. Metal drills are made from high-speed steel grades P6M5, P9, P18 under the general designation HSS, or from hard alloys: VK, T5K10, intended for processing hardened and carbide workpieces.

The drill consists of three elements:

The edges cut into the bottom of the hole and remove thin chips from it.
Spiral cutting forces the chips out of the hole.
The shank is designed to secure the drill in the tool chuck.

It is worth talking about cutting edges in more detail. These are two bevels on the sharp end of the drill that meet at the apex - the most protruding point of the front part, forming a bridge. The angle at which the edges meet is called the principal angle at the apex; its value is standardized for various materials and processing modes:

Hard steel and stainless steel: 135–140°
Structural steel: 135°
Aluminum, bronze, brass: 115–120°
Copper: 100°
Cast iron: 120° clearance angle and 90° edge sharpening angle

Each edge also has its own sharpening angle of about 20–35°, which determines its sharpness. This angle, called the back angle, ensures that the drill touches the metal only along the edges, while leaving free space behind them. This shape is necessary for easier removal and ejection of chips. Some drills have an edge sharpened at a more obtuse angle, even straight. These cutting edges work well on brittle metals such as cast iron, brass and bronze.

The spiral part includes several grooves for removing chips, at the top of which there are additional edges, the plane of which is parallel to the axis of the drill. This is the so-called ribbon, which, when the drill is immersed, cleans the walls of the hole and promotes better alignment.

Types of metal drills and sharpening techniques

Above we looked at the basic type of drills. To understand how angles are formed when sharpening, you just need a little knowledge and practice.

It is best to sharpen drills on a grinding machine with a tool rest; in the worst case, you can use a universal sharpening machine.

Drills cannot be sharpened with an angle grinder: firstly, this is contrary to safety regulations when working with this power tool, and secondly, due to the high rotation speed, the metal overheats greatly and is released, becoming soft.

When sharpening, the drill is placed on a tool rest so that its cutting part is slightly raised. By turning the drill and moving the shank to the left, you need to ensure that the cutting edge is positioned strictly horizontally and parallel to the end of the circle. You need to sharpen the left and right edges alternately, removing a thin layer of metal and periodically cooling the drill in water.

If you simply fix the drill in the required position and bring it to the sandpaper, you will not be able to properly grind the back surface. Due to the fact that the sharpening stone is round, the back of the edge is concave.

This leads to rapid dulling of the edge and problems with chip removal. To avoid this phenomenon, the front part of the drill, after touching the stone, needs to be lifted slightly, moving forward and without removing the pressure.

This creates a convex rear surface, which absorbs the cutting load much better.

Turning of edges should be carried out until sharp edges are removed without chips or burrs. In this case, the removal on both sides should be uniform, which can be judged by the shape and position of the remaining bridge, as well as by the length of the edges themselves. If the bridge is displaced, the drill will rotate eccentrically, which will lead to an increase in the diameter of the hole. This effect can be used if a drill of the required diameter is not available.

When the main edges are brought out, the jumper is stitched. To do this, the drill must be placed on the tool rest at an angle of about 45° and pressed with its back against the edge of the circle, without touching the cutting edge. Two small notches are formed on the jumper, up to 1/10 of the diameter of the drill, which act as leading and centering edges.

A more specific type of drill is used for drilling thin sheet metal. When making a deep hole, the drill is first centered at the tip, and at the exit is held by the strips of the spiral part. However, in thin metal, the apex goes all the way through before the strips hit the edges, causing the hole to be jagged, offset, or oval.

In such situations, it is better to use a feather-type drill with a centering nose. This can be made from a regular metal drill by sharpening it in a certain way.

Everything is done in the same way and with the same angles, but the edges are not turned from top to edge, but are brought together towards each other. The feather drill must be sharpened on the edge of the stone, leaving the bridge intact.

The edges are stitched until the bridge forms a nose protruding 1–2 mm above the tops of the cutting part.

The third type of metal drills is tapered stepped drills. They have several cutting edges of different diameters, which allows you to make holes of different sizes with just one tool. However, despite its apparent versatility, it is quite difficult to find a really good step drill, and it will cost at least $25. Another disadvantage is that such drills can only be sharpened on a specialized machine.

For drilling hard alloys and hardened steel, it is better to use Pobedit drill bits for concrete. Their sharpening is initially designed for crushing action, but if you bring out the edges at an angle at the tip of about 135° and sharpen them at an angle of 20°, even in a very hard part you can make a neat hole without effort.

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How to drill metal correctly

Regardless of whether drilling is performed with a drill or on a machine, the main thing is to choose the right rotation speed. In most cases, the optimal speed is in the range of 1800–2500 rpm, but in practice completely different values can be selected depending on the sharpening accuracy and the properties of the material.

For efficient and fast drilling, you cannot do without the ability to correctly match the rotation speed and feed force. It is easy to feel how the drill cuts into the metal, continuously releasing chips, and itself begins to penetrate into the bottom of the hole without significant effort. The speed is usually quite low - about 300-500 rpm.

The best indicator that the drilling process is technologically correct and the drill is sharpened correctly is the uniform output of chips from both spiral flutes. The quality of the chips is also a significant indicator:

when drilling steel, solid chips are released in the form of long spirals;
cast iron, hardened steel and other brittle materials form a scattering of needles;
aluminum is drilled to form short curls;
When drilling stainless steel, dust and small flakes can be produced.

If the drill does not cut into the metal, but rubs along it with a characteristic squeak, or an atypical type of chip is formed at the output, it is better to stop and correct the sharpening, otherwise there is a risk of the metal releasing due to overheating or breaking the working part.

Be sure to follow safety precautions! You should drill without gloves, protecting your eyes with locksmith goggles.

Before you start drilling, you need to mark all the holes that need to be made in the part. The center of each hole should be marked with a center punch. First, a small hole 2–3 mm deep is drilled, and a few drops of machine oil are added into it. You need to learn to let the drill do its job: first press the tool firmly, and when the edges cut into the metal, release the pressure and just press lightly, maintaining a uniform rotation speed.

Other coolants can be used instead of oil. So, when drilling stainless steel, the drill must be moistened with oleic acid. Its fumes are harmful, so you need to wear a respirator when working. Kerosene and soapy water are also good for cooling - a liter of household bar.

Particular attention is required at the moment the drill comes out when drilling through holes. Quite often in such cases, the thin bottom breaks through with the formation of large burrs, which fall into the spiral grooves and pull the drill forward. At the exit from the part, you need to loosen the pressure and slightly increase the speed.

It is better to drill holes of large diameter in several stages, gradually increasing the diameter of the drill. This will not only reduce the stress on the tool, but will also extend the life of the sharpening and ensure a clean finish. Holes with a diameter of over 13 mm are best drilled using crowns.

It is recommended to use grease instead of oil, this will reduce splashes.

The bit must be periodically allowed to cool down, and during operation, carefully ensure that the teeth are immersed evenly, in other words, keep the spindle strictly perpendicular to the surface of the part.

The final stage of drilling is chamfering both sides of the hole. To do this, you can use a countersink, or, in its absence, a drill of twice the diameter, which is fed with minimal effort at high speeds. To remove burrs from large holes, it is wise to use a round file and sandpaper. published econet.ru

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Source: https://econet.ru/articles/sposoby-sverleniya-metalla-svyorla-i-prisposobleniya

How to sharpen drills for metal correctly - Machine tools, welding, metalworking

The arsenal of any craftsman, both beginner and experienced professional, includes drills. The sharpness of the cutting part decreases over time, and the drill wears out and becomes dull.

When it is necessary to make holes in metal products, it becomes obvious that using such a tool is not only inconvenient, but even dangerous.

Therefore, it is so important to restore the geometry of the gimlet in time and understand how to sharpen a metal drill at home.

Sharpening drills at home

When sharpening is necessary

In order for cutting devices to function well, every master must study information about the correct sharpening of the drill. The operation of this cutting tool consists of rotational movements with axial feed. With its help, it is possible to drill both through holes in metal and existing ones. The diameter and depth of the holes can vary greatly depending on the size of the drill itself and its angle of inclination.

Visual structure of a twist drill

Types of metal drills:

Flat. With their help you can make deep holes of large diameter.
Spiral.
Centers. Used for centering elements.
Ring.

Absolutely all devices become dull and lose their sharpness over time, which interferes with work. But how can a beginner or an inexperienced craftsman understand that sharpening is already necessary? Let's look at a number of signs that indicate that the drill needs to be sharpened urgently:

The appearance of an unpleasant hum and a sharp squeak indicates wear of the cutting device.
The edges quickly heat up during drill operation, and heat does not dissipate from the cutting angle. The corner, in turn, becomes blunt, losing its sharpness and becoming rounded. After this, the edges and edges wear out, which contributes to overheating of the tool.
The holes in the metal become insufficiently deep, unclear, and their quality decreases. Metal shavings come out incorrectly. Metal shavings come out

Equipment

Sharpening must be carried out using specialized equipment in compliance with safety precautions. In order not to harm yourself, you should remember a few nuances:

Eye protection.
Availability of a container with liquid for cooling the instrument.

Source: https://stanki-info.com/kak-pravilno-tochit-sverla-po-metallu/